This invention relates to the control of a cooling fan on a work machine, and, more particularly, to a control algorithm which controls the speed of a cooling fan as needed by controlling the amount of power provided to the fan.
A work machine, such as a wheel loader, hydraulic excavator, forwarder, or track-type tractor typically generates a great deal of engine heat during operation. This engine heat is often exacerbated by a high ambient temperature at the work location. Additionally, in an effort to make the machine operate more quietly, the engine compartment of the machine is often heavily muffled and insulated, which also raises the engine compartment temperature. It is therefore desirable to run a cooling fan or other airflow provider to draw, push, or otherwise direct heat away from the engine compartment.
Conversely, often regulations require that the noise produced by the work machine be less than a predetermined level or rate. As much of the noise produced by the machine is caused by the cooling fan of the machine, it is thus advantageous to regulate the operation of the cooling fan to provide the least amount of noise while still maintaining the desired cooling characteristics. This is often done by running the cooling fan at a reduced speed or by selectively turning the fan off.
An example of a cooling fan control algorithm is disclosed in U.S. Pat. No. 6,045,482, issued Apr. 4, 2000 to Dipchand V. Nishar et al. (hereafter referenced as ""482). ""482 discloses a system for controlling air flow to an engine cooling system which includes a control computer responsive to a number of engine and/or engine accessory operating conditions, and to various engine operational states to control operation of an engine cooling device. Examples of the engine and/or engine accessory operating conditions include engine coolant temperature, rate of change of engine coolant temperature, intake manifold air temperature, air conditioner refrigerant pressure, and fan speed factor.
Accordingly, the art has sought an apparatus and method of a cooling fan control system for a work machine which: measures one or more temperature inputs from the work machine; controls the cooling fan without requiring that the cooling fan be monitored; controls the cooling fan to provide a reduction in noise produced by the work machine; proportionally modulates a pump which directly drives a motor; limits the rate of change of the proportional modulation to prevent driver diagnostics and hydraulic system instabilities; provides lower fuel consumption; provides reduced overcooling of the engine inlet air and hydraulic fluid in cold ambient conditions; provides greater operator comfort; may be used in a timely and efficient manner; and is more economical to manufacture and use.
The present invention is directed to overcoming one or more of the problems as set forth above.
In an embodiment of the present invention, a method for controlling a fan on a work machine is provided. The method includes the steps of producing an inlet manifold air temperature signal responsive to a sensed temperature of air at an inlet manifold, producing an engine coolant temperature signal responsive to a sensed temperature of an engine coolant fluid, producing a hydraulic sump temperature signal responsive to a sensed temperature of a hydraulic fluid, and producing a transmission lube oil temperature signal responsive to a sensed temperature of a transmission fluid. The method also includes the steps of reading the inlet manifold air temperature signal, engine coolant temperature signal, hydraulic sump temperature signal, and transmission lube oil temperature signal and responsively calculating a fan current value; and reading the fan current value and responsively controlling the fan.
In an embodiment of the present invention, an apparatus for controlling an engine cooling fan is provided. The apparatus includes one or more temperature sensors, an electronic control module, and a fan control device. The temperature sensors are adapted to measure one or more temperatures and responsively produce one or more temperature signals. The electronic control module is adapted to receive the temperature signals and responsively produce a fan current signal. The fan control device is adapted to receive the fan current signal and responsively control a driving force provided to the engine cooling fan.
In an embodiment of the present invention, a method for use in an engine cooling system for a work machine is provided. The method includes the steps of generating a current signal based on at least one temperature input, and reading the current signal and responsively providing power to a cooling member.